Implementing VoIP at an institution using the SIP.edu cookbook

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Dennis Baron, May 14, 2006 Page 0

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SEEREN2 Winter School, Kopaonik, Serbia, VoIP workshop

Dennis Baron

Milivoje Mirovic, AMRES March 12th_{, 2007.}

Implementing VoIP at an institution

using the SIP.edu cookbook

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Motivations

• Provides a useful service

• Easy to get started

• Lots of options

• Facilitates inter-campus communications

• Opens the way for innovation

• Build I/T staff skills

• Help break down organization/cultural barriers

• Encourage early technology adopters

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Means

• Publishing “cookbook” with several alternative

“recipes”

• Obtaining corporate sponsorship and promotional

pricing

– Cisco, Avaya, etc.

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Goals

• SIP Connectivity

Build a large base of SIP-reachable NREN users by making

existing campus PBX, Centrex, and VoIP systems reachable via SIP

• SIP Addressing

Facilitate the convergence of communications identities by promoting the use of email addresses for voice and

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Components

• DNS Server

– Add SIP SRV records to existing servers

• SIP Proxy Server

– Also acts as SIP registrar

– Can support “aliases” for legacy phone numbers – Mimics campus dial plan

• LDAP Server (or other source of directory data)

– Has mapping of email to phone number

• SIP Gateway

– Connects to existing PBX or Centrex

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Dennis Baron, May 14, 2006 Page 6 np143 PBX PSTN SIP/PRI Gateway

SIP.edu Configuration

SIP Server Campus Network Internet2 DNS Server LDAP Server

SIP user wants to call

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DNS SRV Lookup

SIP Server DNS Server LDAP Server Campus Network Internet2 DNS SRV DNS lookup for MIT.EDU

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SIP INVITE

SIP Server DNS Server SIP LDAP Server Campus Network Internet2 SIP INVITE to [email protected]

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LDAP Lookup

SIP Server DNS Server LDAP LDAP Server Campus Network Internet2

LDAP lookup for dbaron – returns x21232

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Call Sent to PBX Gateway

SIP Server DNS Server SIP LDAP Server Campus Network Internet2 SIP INVITE to x21232 via Gateway

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Media Stream via Gateway to PBX

SIP Server DNS Server RTP LDAP Server Campus Network Internet2

SIP user talks to [email protected] at x21232

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Sip to SIP Calling

SIP Server DNS Server RTP LDAP Server Campus Network Internet2

SIP user talks to [email protected] at his SIP phone

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SIP to PBX and PSTN Calling

SIP Server DNS Server LDAP Server Campus Network Internet2

Campus SIP user calls 21232 or 912129990000

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Dennis Baron, May 14, 2006 Page 14 np143

Architecture (Phase 1)

SIP

Proxy

DNS

SIP-PBX

Gateway

PBX

INVITE (sip:[email protected]) INVITE (sip:[email protected]) DNS SRV query sip.udp.bigu.edu telephoneNumber where mail=”bob” PRI / CAS bigu.edu Campus Directory SIP User Agent

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Call Flow Example

• SIP DNS lookup for MIT.EDU points to SIP proxy

– Sends INVITE to [email protected] to proxy

• SIP proxy checks MIT directory

– Maps call to PBX extension – eg. [email protected]

• SIP proxy checks dial plan

– Routes call to PBX gateway

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DNS

INVITE (sip:[email protected]) DNS SRV query sip.udp.bigu.edu bigu.edu SIP User Agent

Architecture (Phase 2)

location DB

If Bob has registered, ring his SIP phone; Else, call his extension through the PBX.

REGISTER (Contact: 207.75.164.131) INVITE (sip:[email protected])

SIP

Proxy

SIP

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Examples – Vendor Solution

• Avaya

– SIP Converged Communications Server (CCS)

– Communications Manager Media Server and

Gateway

• Handle Based Dialing service (LDAP plugin)

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Examples – All-in-One

• Asterisk as both proxy and gateway

• Soekris 4801 server with Sangoma

T1/E1 card

– Approximately $675USD

• Astlinux (Asterisk + micro Linux)

• Directory lookup via file or LDAP

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“gaps”

• SIP is more than voice

– Video and IM are important too

– Presence services change the user experience

• Chickens without eggs only gets you half way

– We’ve made everybody SIP reachable, now who’s going to call them?

• The 12-digit keypad problem will be with us for

awhile

– What do we do until the devices have a 21st _{century user}

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Cookbook Status

See

http://mit.edu/sip/sip.edu/

• Sections have been added

– Cisco SIP Proxy Server (CSPS) – Cisco Gateways

• Missing pieces

– Asterisk gateway

• Some information is over two years old now

– Proxy and gateway sections could be updated for current releases

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Vendor Support SIP.edu work

• Avaya

– Developed LDAP plug-in for directory integration – Sponsored first SIP.edu hands-on workshop

• Cisco

– Discount package for CSPS

• Comcast

– Sponsored first SIP.edu implementers workshop

• Pulver.com

– Developed BlueLava package for SER/Asterisk – Workshop support – software and instruction

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Addressing

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+1-734-352-7031

Deep bureaucratic hierarchy

Telco provider control

[email protected]

The world is flat (almost)

Be your own provider

Radically new devices / services

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Why Phone NUMBERS?

• Users should not be burdened with device addresses, when it’s people they really care about

• Addresses should be mnemonic and empower enterprises to manage the identities of their users

sip:[email protected] • It’s time to put E.164 phone

numbers behind us!

• A.G. Bell did not say:

“+1-617-252-1232, come

here. I need you!”

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Cell Phones

IP Desk

Phones

Legacy Desk

Phones

PSTN

Old World*

Emerging

New World

Solution:

numeric aliases

* Transitional period during which we have to support these devices will last a long time!

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• 4257*260

• ITADs

–Defined by Telephony Routing over IP (TRIP)

[RFC3219]

–Globally unique

–Lots of them (2

32

_{- 256)}

–IANA is already set up to allocate

• ISN resolution works just like ENUM

locally

assigned IP Telephony Administrative Domain (ITAD)

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Dennis Baron, May 14, 2006 Page 28 np143 Academic – Internet2 – Hofstra University – UCLA – MIT – Stanford

– University of Alaska Fairbanks – University of California, Berkeley – Florida State University

– University of Manitoba – University of Oregon

– Royal Institute of Technology – NE Worcestershire College – Trent University

– University of North Carolina – University of Texas, Austin – Columbia University

– UCSD

– Taiwan Academic Network

Corporate Enterprises

– Sterling National Bank

– Apple Computer _{VoIP Service Providers} – Free World Dialup – Stealth Communications – SIPcall.com – RCN Corporation – VoIPteq – SIP Broker Other

– BizFu (web hosting)

– Manitoba New Democratic Party – Packet Clearing House

– +36 others

VoIP Solution Providers

– Tello – Iotum – Digium

Government

– State of Oregon

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• Trial just starting up

– Supported by Internet2, Packet Clearing House,

MIT, Tello

• ISN Cookbook Published

– Recipes for SER and Asterisk

• 103 ITADs assigned so far

–

http://www.iana.org/assignments/trip-parameters

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1. Request an ITAD from IANA – Simple piece of email

– Approximate two week turnaround

2. Publish your ITAD/ISN information in DNS – Option1: Put full NAPTR in root zone

*.xxx.freenum.org IN NAPTR 100 10 "u" "E2U+sip” "!^\\+*([^\\*]*)!sip:\\[email protected]!" .

– Option2: Have root zone delegate to your own nameservers 3. Enable inbound ISN calling

4. Enable outbound ISN calling – Option1: Native ISN lookup

– Option2: Using Tello SIP redirector

– Option3: Using Tello private ENUM

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Dennis Baron, May 14, 2006 Page 31 np143 E.164 GDS ISN +1-734-913-4257 Phone numbers ITU, national government, … Hierarchical / geographical Non-numeric Characters

Ignored No * Only Yes

Varies by country ??? 00 1 189 7349134257 Public ENUM + multiple private ENUMs H.323 video users 4257*260 Huh? IANA local*domain With domain owner’s cooperation ViDeNet, national gatekeepers Hierarchical / geographical/ organization One space With domain owner’s

cooperation

One space

SIP AOR

Example [email protected]

Familiarity Email addresses

Delegating Authority ICANN, TLD registrars Address Structure local@domain